Various nitrogen compounds and plant nutrients are known to be desirable for fertilizing various plants, in particular crops. Repeated adding of fertilizer to crops however can be time consuming and costly to both purchase and distribute to the plants.
While forms of nitrogen are known to exist in large quantities in exhaust gases of combustion engines, these forms of nitrogen however are typically harmful to the environment and of little use as a fertilizer.
U.S. Pat. No. 6,446,385 to Crutcher describes a greenhouse system in which a gas turbine provides heat and power to maintain the greenhouse. An exhaust gas treatment system receives the hot gas from the turbine to remove and convert harmful nitrogen compounds while a fertilization system makes use of the converted nitrogen compounds as fertilizer for feeding the plants of the greenhouse. The method of extraction described refers to European patent application No. 97117779.5. The gas treatment system however requires consumption of an alkaline earth compound to react with nitric acid which is formed to then form an alkaline earth nitrate in an aqueous form. The resulting calcium nitrate or magnesium nitrate which may be produced are harmful to the plants and soil when distributed in excess quantities and accordingly this system would require careful monitoring so that only limited amounts of the fertilizer compound generated by the gas treatment system are in fact distributed to the plants through irrigation thereof in the greenhouse. This method converts NOx to nitric acid to be scrubbed out with earth alkaline in an aqueous effluent, leaving carbon dioxide in the exhaust stream to raise the carbon dioxide levels in the greenhouse.